Re: Surface Transportation Board STB and narrow gauge

STB only deals with railroads that are common carriers.

White Pass and D&SNG might still have that status, but I doubt any other US narrow gage does. If they are common carriers, they would also be paying into Railroad Retirement instead of Social Security.

The FRA is a little murkier - they would have authority over any common carrier, and generally not anything they define as an "insular railroad". However, crossing a public highway or waterway, or operating within 30 feet of a common carrier usually the FRA will claim some kind of safety oversight. Basically Congress assigned the FRA railroad safety oversight, and the FRA gets to define what they want to oversee.